A proposal has been made of an image forming apparatus that allows the time of printing to be specified, wherein, in order to prevent the sheets on a sheet feed tray from being used for other purposes and becoming insufficient during the course of time from setting of the printing time to the formation of an image, the number of specified sheets stored in the sheet feed tray is compared with the number of sheets with an image to be formed thereon; and if there is a shortage of sheets, a warning is issued to replenish the sheets (e.g., Patent Document 1    [Patent Document 1] Unexamined Japanese Patent Application Publication No. 10-133530
The image forming apparatus described in Patent Document 1, however, outputs the warning to prompt sheet replenishment whenever there is a shortage of specified sheets from setting of the printing time specification job up to the advent of the specified printing time.
Thus, if there is a shortage of sheets, a warning for prompting replenishment is issued, even when there are several months before the specified printing time and there is still time before the specified sheets are to be replenished without immediate need for replenishing the specified sheets. Then the operator having specified the printing time or the other person working close to the image forming apparatus has to replenish the sheets in response to each warning or to release or ignore the premature sheet replenishment request. This method imposes unwanted (premature) work load on the operator.